X-Junk-Score: 0 [] X-Cloudmark-Score: 0 [] X-Cloudmark-Analysis: v=2.3 cv=NIirBHyg c=1 sm=1 tr=0 a=EmBPEBpMjP/3QNnZKm4stQ==:117 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=x7bEGLp0ZPQA:10 a=ad1WmcueCrwA:10 a=oexKYjalfGEA:10 a=HZJGGiqLAAAA:8 a=Ia-xEzejAAAA:8 a=m-mLqZ2HsLlfHsgaBhIA:9 a=QEXdDO2ut3YA:10 a=W07W-IZlYDpX3WD_JfMA:9 a=I6-HZ3nyl5a5GCoN:21 a=Urk15JJjZg1Xo0ryW_k8:22 From: "William Jepson wrjjrs@gmail.com" Received: from mail-ed1-f54.google.com ([209.85.208.54] verified) by logan.com (CommuniGate Pro SMTP 6.2.12) with ESMTPS id 12400355 for flyrotary@lancaironline.net; Tue, 02 Apr 2019 15:48:02 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.208.54; envelope-from=wrjjrs@gmail.com Received: by mail-ed1-f54.google.com with SMTP id d11so3010426edp.11 for ; Tue, 02 Apr 2019 12:48:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=IItTcfhI6TpRDPCQcbvRxmFMGnuVGwY/JfKENJcNcm4=; b=kvFVzPPEgv79D86v53fyqbG+P9n/ysrd4pPSbAqN5R572f9Do8sVUYS1HcFsnih3VL nu6rdr2X2UzqMQaso2xWJUi8sUUEeyxSsu2cbXnlk/7zhNS13tBjFCfUb2GSE6N4o1Ip 5Niiymn0kVTooUHkyzpZoMGtpKIliuyuwHUoc1TOgRTPVl9q6OnWljoWJ0991f1k/+Ax Td19KFBEnbfYDH2H3Qsa1suegiDe6loxSqGm7+mum8iEpsWn7ykDb78v7eIAwRphM4hO BgxBtr0I8Nq2ndGWKcai95y+AjDMLZkJxg3taJBEX9sAI28xhbFjkX7x2248dBdEmnci 3c0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=IItTcfhI6TpRDPCQcbvRxmFMGnuVGwY/JfKENJcNcm4=; b=hniP7RrP+niwMkSw3sgVkctpB8W9j032Y/unr35BGfqvaX14o/GjFJMIkjTpYzkhcc Dq4v0yFLxst4tUP8HChFE7fK2gqIRDXZWWpGW9Dc54L3Qloy9f4ZzLT8P4620Ez9PE1e dhPClnpRpu4WkY159LfG2yX3uEWCPkf8zZIE3mQDaLXR0aGpwsTm8RMtp71JB+GxczRZ HH0IVTqXsS6zP35bz6Sm7zrk5VDsEUxpYGfUJB++tJ0Xha5t82bm1C1bXH9Tds6IWgAf q2m+/vR0SJZnCVWmRClN6ZsWpPc1Nibqv9FM2jds+XqQJ6lUYNld1uuvW6dVEcZdee1J UW2A== X-Gm-Message-State: APjAAAVu1KsWC8dCKAxl3Fw7aBeVy0+gdibVsikzAPpQsmIu1XaFrsnq sq3ejR/2v40CXVAtQ4S34IuZJ7CTNv5XRZnkxuVb6w== X-Google-Smtp-Source: APXvYqw3IdFAwyfK3z8iQRVn73hz/Vig40Fx8HcdKcZn01JeeM1ShZQsrlF/PlsglgGVXXDxLdnXjpqkredcW31NPeo= X-Received: by 2002:a17:906:33c7:: with SMTP id w7mr41610605eja.191.1554234463903; Tue, 02 Apr 2019 12:47:43 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: Date: Tue, 2 Apr 2019 12:47:32 -0700 Message-ID: Subject: Re: [FlyRotary] Electric constant speed props To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="0000000000001e6815058591699d" --0000000000001e6815058591699d Content-Type: text/plain; charset="UTF-8" Sam, I am working with some originators of Powersport. The weight of your build makes a big difference on the use of a constant speed. Also in the case of the rotary the quality of your muffler! Sound levels really effect your comfort on longer flights. Mufflers for rotaries are tough, I already have 1 failed design to my (bad) credit. The original Powersport designs used the light weight and flexibility of a wood prop to their advantage. Those engines were tuned for max power at 6500 RPM. The reductions were about 1.85 to 2.2:1. suitable for the lower power peak. Torsional vibration issues also favored a wood prop. How heavy is the electric Airmaster? MOST engines including the rotary are helped by a variable pitch prop. Whether the combination is safe depends on the reduction drive, ratio, and weight of the prop on the output shaft. Powersport's owners noted significant torsional vibration problems with every planetary gear set, (even their own custom made straight cut planetary). Their later stiff model internal ring gear reduction gearbox put the resonances out of the normal range for the rotary. Prior to that the only problem free build with a planetary was when they built a pendulous damper system (like a big radial engine uses) which worked great but was so expensive they figured they would never sell an engine. So if you are running a planetary reduction you need to keep the weight down as much as you can. Find out what the Airmaster weighs. The amount that it exceeds your wood or carbon fixed blade prop is your risk factor. The advantage is to use a low cruise rpm that takes advantage of the props flexibility. As a thrust producing device it is better, there is no doubt. If it is very heavy though it may cause problems that aren't obvious as to origin. Torsional problems may take hundreds of hours to develop, or something may break the first week. Just be wary. Always keep track of things like changes in output shaft end play and backlash. You can make the change, and see excellent results but go in with your eyes open. Lots of people will tell you this is nervous nelly stuff, but the guys at P.S. probably had more hours running and testing rotaries AT HIGH OUTPUT levels than anyone other than Mazda. Bill Jepson On Tue, Apr 2, 2019 at 6:34 AM Samuel Hodges samueln462wp@att.net < flyrotary@lancaironline.net> wrote: > Lately I have been considering an Airmaster electric constant speed prop > to help achieve the rotaries true potential. I am asking for insight to > help me make this decision. I'm not sure if the benefits of a constant > speed out weight the cost, please help. > > Sam > RV-7A > Renesis > --0000000000001e6815058591699d Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Sam,
I am working with some originators of Powersport. The weigh= t of your build makes a big difference on the use of a constant speed. Also= in the case of the rotary the quality of your muffler! Sound levels really= effect your comfort on longer flights. Mufflers for rotaries are tough, I = already have 1 failed design to my (bad) credit. The original Powersport designs us= ed the light weight and flexibility of a wood prop to their advantage. Thos= e engines were tuned for max power at 6500 RPM. The reductions were about 1= .85 to 2.2:1. suitable for the lower power peak. Torsional vibration issues= also favored a wood prop. How heavy is the electric Airmaster? MOST engines includin= g the rotary are helped by a variable pitch prop. Whether the combination i= s safe depends on the reduction drive, ratio, and weight of the prop on the= output shaft. Po= wersport's owners noted significant torsional vibration problems= with every planetary gear set, (even their own custom made straight cut pl= anetary). Their later stiff model internal ring gear reduction gearbox put = the resonances out of the normal range for the rotary. Prior to that the on= ly problem free build with a planetary was when they built a pendulous damp= er system (like a big radial engine uses) which worked great but was so exp= ensive they figured they would never sell an engine. So if you are running = a planetary reduction you need to keep the weight down as much as you can. = Find out what the Airmaster weighs. The amount that it exceeds your wood or carbon fi= xed blade prop is your risk factor. The advantage is to use a low cruise rp= m that takes advantage of the props flexibility. As a thrust producing devi= ce it is better, there is no doubt. If it is very heavy though it may cause= problems that aren't obvious as to origin. Torsional problems may take= hundreds of hours to develop, or something may break the first week. Just = be wary. Always keep track of things like changes in output shaft end play = and backlash. You can make the change, and see excellent results but go in = with your eyes open. Lots of people will tell you this is nervous nelly stu= ff, but the guys at P.S. probably had more hours running and testing rotari= es AT HIGH OUTPUT levels than anyone other than Mazda.
Bill Jepson

On= Tue, Apr 2, 2019 at 6:34 AM Samuel Hodges samueln462wp@att.net <flyrotary@lancaironline.net> wrote:
=C2=A0Lately I have been cons= idering an Airmaster electric constant speed prop to help achieve the rotar= ies true potential. I am asking for insight to help me make this decision. = I'm not sure if the benefits of a constant speed out weight the cost, p= lease help.

Sam
RV-7A
Renesis= =C2=A0
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